1. Field of the Invention
The present invention relates to an insertion tool, and more particularly relates to an insertion tool for inserting a multi-strand twisted cable into a blind hole, and more particularly relates to an insertion tool that is adapted to fit onto the outer surface of a multi-strand twisted cable, as opposed to an insertion device that grips onto a sleeve, collar, head, shaft or other driving means for the cable.
2. Description of the Prior Art
In underground mining, it is conventional practice to support a mine tunnel roof by boring holes up into the roof and thereafter inserting elongate "rock anchors" into these holes, using a conventional bolting machine. Such a bolting machine includes an extended boom arm having a rotating and driving means on the end thereof in a manner to accept the shank of a drill bit and rotate and urge the drill bit up into the bore hole, thereby drilling the bore hole in the mine tunnel roof. The boom arm driving means is then used to rotate and drive the elongate rock anchor into the bore hole. Thereafter, the rock anchor is tightened in order to put the roof rock formation (rock, earth, etc.) above the main tunnel roof into compression, thereby tightening the formation and lowering its potential for fracture, deformation, and therefore failure. Other types of elongate rock anchors are cemented or grouted into these mine roof bore holes in order to adhere the mine roof rock formation to the rock anchor in a manner that the rock anchor both supports the mine tunnel roof rock formation directly above the tunnel, and also is supported by the material above that.
Customarily, these rock anchors have been formed of solid elongate bolts or steel rods having heads formed on one end thereof, the head being utilized as a conventional bolt head to: (1) drive the elongate rock anchor up into the hole in the mine tunnel roof; and (2) in combination with a large flat washer and what are called "roof mats", support the mine tunnel roof rock formation directly above the roof.
The last few years have seen the introduction of a flexible multi-strand steel cable as this elongate rock anchor, in place of a rigid elongate bolt or steel rod, in certain types of rock and earth formation above the mine tunnel. In order to utilize a cable in place of a steel headed bolt in this application, it has heretofore been necessary to install a head or some sort of driving and retaining mechanism on the end of the cable that could be utilized by the bolting machine to insert the cable up into the mine tunnel roof blind bore hole. The bolting machine has been used to install the solid bolts and shafts, and also cable sections having a driving head affixed on one end thereof.
It has been determined that in certain rock formations, a bolt head becomes unnecessary to retain the rock formation in compression, because of the fact that the rigid bolt (or cable as the case may be) is cemented or grouted to the interior of the mine roof bore hole along essentially its entire length, thereby removing the possibility of additionally compressing the rock formation above the mine roof once the mine roof bolt or cable is installed. In these situations, it is apparent that the head formed on the rigid bolts or rods and attached to the end of a section of cable was necessary only for inserting the bolt, rod or cable up into the mine tunnel roof bore hole. Once the rock anchor was cemented or grouted in place inside the bore hole, the head used to insert the anchor into the bore hole became essentially useless.
Inasmuch as conventional mine roof bolts are relatively inexpensively formed with heads thereon, it is common practice to use the head to insert the bolt into the mine roof bore hole in the conventional manner. However, when utilizing a multi-strand twisted steel cable as the rock anchor, it became a relatively expensive process to form and attach a headed member on one end of the cable for single purpose of installing the cable in a mine roof bore hole.